1. There is a finite number of Bitcoins that will exist

This is a good thing. It makes Bitcoins similar to gold. There is a finite amount of gold in the world. Artificial scarcity is an innovation.

    2. Whilst there is a finite number of bitcoins, 
    there are an infinite number of Bitcoin-substitutes

That's true, but the network effect, being first to market, and having an enormous community counts for a lot. There is only one Facebook. Also it would take lots of additional software overhead for businesses to support other currencies in addition to Bitcoin, not to mention it would confuse consumers.

    3. Large companies couldn’t adopt Bitcoin, even if they wanted to

Then explain how Shopify adopted Bitcoin? This is simply incorrect.

    4. Trust and transparency"

If someone steals your Bitcoins, they committed a crime, and the police will go after them. Bitcoin also leaves a great audit trail.

    Continued existence of currency – as noted in
    section 3 above, whilst there may be good reasons 
    why cryptocurrencies could replace traditional
    currencies, there is absolutely no basis for assuming
    that Bitcoin will be that winning currency.

Yes there is a good basis - the fact that it's survived for 4 years as the leader. TCP/IP, HTML, etc. is still around.

    5. Reliance on cryptography

Everyone relies on cryptography nowadays, and in the slim chance it becomes broken, the Bitcoin community would come up with a new encryption scheme.